Aircraft typically require complex, heavy, mechanical flap surface actuation systems for vehicle flight stability and control. While very effective aerodynamically, these flap-based controls require powerful and heavy hydraulic or electric actuation systems to move the flap effectors. Furthermore, the flap surfaces are structurally inefficient in that they introduce discontinuities in the airframe surface which requires additional structural weight for support. Current emphasis for next-generation aircraft require a dramatic reduction in airframe weight and cost while maintaining performance and capability.
Active flow control involves modification of the turbulent structure of eddies in most complex flows with the intent to improve aerodynamic performance of air vehicle flight control and propulsion systems. Such capability can increase range and maneuverability, reduce acoustic loads, signature, weight, and cost. In some systems, a relatively small amount of high-momentum secondary fluid is used to enhance the naturally occurring instabilities of the main flow. For example, it is known to use active flow control in applications such as favorably influencing the flow over aerodynamic surfaces, heating/cooling components, vectoring a primary fluid flow, and mixing fluids.
The aerodynamic design and integration of the control surfaces within next generation aircraft plays a major role in determining the capability and configuration of these aircraft. Next generation tailless aircraft will be highly integrated where components are buried or submerged into the platform. Additionally, exotic shapes may cause excessive propulsion performance losses. These losses may emanate from strong secondary flow gradients in the near wall boundary of the fluid flow, which produce large-scale vertical flow field structures. Flow field detachments may produce increased body drag and aerodynamic buffeting. All of which compromise the integrity and capability of these aircraft.
In the past, adverse flow fields were avoided or addressed by the aircraft's design. Alternatively, active control surfaces have been used to address flow field structures associated with exotic shapes. For example, the overall aircraft could be lengthened to prevent aft body flow field detachments or additional control surfaces could be incorporated into the vehicle to also prevent aft body flow field detachments. Other solutions may have required that certain components be structurally hardened (increasing weight) or replaced more frequently to avoid failures resulting from these stresses. Components may also be repositioned to non-optimal positions to reduce these stresses. However, these situations often result in reduced vehicle performance. Similarly, adding structural weight to support increased stress loads also results in reduced vehicle performance.
The aerodynamic design and integration of the control surfaces plays a major role in determining the capability and configuration of aircraft such as the unmanned aerial vehicle (UAV), long-range strike (LRS), and multi-mission air mobility systems. To enable advances in vehicle design, groundbreaking aerodynamic technologies are required to integrate control surfaces into these advanced platforms. New technologies are required to meet the more restrictive requirements associated with reduced weight/volume and mechanical complexity while aerodynamically accommodating exotic vehicle shaping requirements, without compromising functionality and performance.
To address integration issues associated with control surfaces, previous solutions required additional hydraulic and structural systems to support the required control systems. The consequences of such solutions compromise vehicle capability.
New technology is therefore needed which will allow greater freedom to integrate control systems within advanced aircraft designs. The benefits of such integrated designs for advanced planforms will be to enable reduced vehicle size and weight, favorable movement of vehicle center of gravity (Cg) forward, reduced drag, reduced aft body structural heating, and improved flight performance. Application of such a technology is not only limited to being a design enabler for future all-wing air-vehicle designs, but also could be applied to existing aircraft to improve vehicle control.
Further limitations and disadvantages of conventional control surfaces and related functionality will become apparent to one of ordinary skill in the art through comparison with the present invention described herein.